1. Field of the Invention
The present invention relates to a mounting adapter for mounting a rotor to the spindle in a centrifuge instrument, the adapter being of the type having a locking taper surface thereon adaptable to engage a correspondingly tapered surface on the drive spindle of the instrument and, in particular, to an adapter provided with a removal arrangement for separating the engaged tapered surfaces of the adapter and the spindle.
2. Description of the Prior Art
The centrifuge instrument manufactured and sold by E. I. DuPont de Nemours and Company Inc. as the RC-5C instrument includes a source of motive energy to which is attached an elongated drive spindle. The uppermost end of the spindle is terminated with an enlarged, generally cylindrical, flexible coupling member. The flexible coupling member is received by a drive spindle/pin assembly, or spud, on which the centrifuge rotor is mounted. The flexible coupling member includes an elastomeric layer bonded to the end of the spindle. The elastomeric layer is surrounded by a cylindrical metal cap. The spud includes a shell member having a cylindrical recess formed therein which accepts the cap of the flexible coupling. The flexible coupling is held in place in the spud by a threaded clamp ring which engages threads formed on the shell. The clamp ring is secured to the outer shell by a set screw to prevent the clamp ring from walking off the shell. The set screw has a nylon tip so as not to mar the threads of the clamp ring. The spud is provided with a generally frustoconical lateral surface and a generally planar upper surface thereon. The planar end surface of the shell has drive pins projecting therefrom. These drive pins, when received within a groove formed on the lower surface of a rotor, act against corresponding pins disposed in the rotor groove to impart rotational motion to the rotor.
With such an arrangement it is diffficult to remove the tapered outer shell member from the spindle. The difficulty primarily attends the insertion of a suitable spanner into openings in the clamp ring. Only when the spanner is properly inserted may an opening torque be applied to the clamp ring to permit removal of the tapered outer member from the end of the spindle.
In the centrifuge instrument manufactured and sold by E. I. DuPont de Nemours and Company Inc. as the OTD ultracentrifuge the upper end of the drive spindle from the oil turbine drive element itself exhibits a tapered surface. The tapered upper end of the spindle is inserted into a correspondingly tapered recess of a rotor drive adapter. The outer surface of the drive adapter is configured to engage a correspondingly shaped recess in a rotor whereby the rotor is directly mountable on the drive adapter. The engagement of the tapered surfaces at the upper end of the spindle and on the inner surface of the adapter form a locking taper fit. A locking taper fit is advantageous because it prevents separation of the rotor from the drive spindle and provides concentricity between the rotor and the spindle.
Due to the presence of the locking taper fit a special tool is required to remove the adapter from the spindle. This tool is clamped about a boss on the outer periphery of the drive adapter. A threaded bolt that is carried within the tool extends downwardly through a central opening in the adapter and rests against the top of the spindle. As the bolt is rotated it acts against the spindle to exert a lifting force on the adapter to raise the same from the spindle.
In view of the foregoing it is believed advantageous to provide a rotor mounting adapter for a centrifuge instrument that uses a locking taper fit but which includes a locking taper removal arrangement whereby the spindle and the adapter can be easily separated from each other.